New Limb on Family Tree

An ancient slope-faced ape nicknamed Pau is filling in a major blank spot in our extended family portrait. The creature, known scientifically as Pierolapithecus catalaunicus, may be the last common ancestor of the great ape family: gorillas, chimps, orangutans, and humans.

Paleontologists Salvador Moyà-Solà and his wife, Meike Köhler, of the Miquel Crusafont Institute of Paleontology in Barcelona initially found a piece of Pau’s skull and a canine tooth two years ago at a site in northeastern Spain. Later excavations unearthed more of the animal’s remarkably complete remains, a total of 83 bone fragments. In life, he weighed between 66 and 77 pounds and stood almost four feet tall.

Pau’s age—12.5 million to 13 million years old—is what really grabbed the researchers’ attention. Evolutionary reconstructions indicate great apes branched off the primate family tree between 11 million and 16 million years ago, but fossils from that period have been sorely lacking. This find offers the first good look at that transitional era.

Like his modern relatives, Pau had a broad, sloping face and a wide rib cage, plus a flexible wrist suitable for tree climbing. At the same time, his small hands were decidedly monkeylike rather than apelike, with straight fingers. That suggests Pau lived primarily in trees but was not adept at swinging from the branches. Moyà-Solà suggests the ability to swing from branches probably evolved independently in chimps and orangutans, long after the two groups diverged.

Although many researchers (including Moyà-Solà) place human origins in Africa, Pau may bolster the notion that humans’ earlier ancestors actually evolved in Eurasia and migrated to Africa. Thus paleoanthropologist David Begun of the University of Toronto thinks the next fossil great-ape discovery might come from Turkey. “The animals would have had to travel from Eurasia to Africa somehow,” he says. “But we’re surprised all the time by what we find.”